Data carrier system

ABSTRACT

When an engine is started with a key  19 A inserted in an ignition key cylinder of a vehicle  11 , a vehicle-side controller  12  transmits operational data to the key  19 A and stores in the key  19 A. Further, when a personal computer  30  is operated with the key  19 A inserted in an R/W device  31 , the R/W device  31  reads the operational data from the key  19 A and transfers to the personal computer  30 . In this structure, when a storage capacity of the key  19 A becomes full, the vehicle-side controller  12  stores the operational data in a storage portion of its own, and when the key  19 A is initialized, the stored operational data is written in the key  19 A. For this reason, even when initialization of the key  19 A is difficult, deletion of the operational data is prevented.

FIELD OF THE INVENTION

The present invention relates to a data carrier system which carries outcommunication of operational data between a vehicle-side control deviceand a receiving device.

BACKGROUND ART

FIG. 27 shows a conventional structure of the above-described datacarrier system. A vehicle 1 is equipped with a vehicle-side controldevice 2. When an IC card 3 is inserted in a holder of the vehicle 1 toallow start-up of an engine, the vehicle-side control device 2 transmitsoperational data (the date and time of start-up of the engine, and thelike) of the vehicle 1 to the IC card 3 and the operational data isstored in the IC card 3. Further, a reading device 4 is installed in anoffice. When a personal computer 5 is operated with the IC card 3 beinginserted in the reading device 4, the reading device 4 reads theoperational data from the IC card 3 and transmits the same to thepersonal computer 5. As a result, the personal computer 5 displays theoperational data on an image surface thereof or stores the same in afloppy disk.

In the above-described structure, when a storage capacity of the IC card3 becomes full, the operational data cannot be recorded in the IC card3. For this reason, when the personal computer 5 is operated, aninitialization command is transmitted to the IC card 3 via the readingdevice 4 and the IC card 3 is provided to clear the operational data.However, initialization with the IC card 3 being carried in an office orthe like may be a difficult operation depending on the existing state ofthings, or management of initialization wherein the IC card 3 is carriedinto an office or the like may be difficult. Accordingly, there is apossibility that the operational data may not be surely recorded.

The present invention has been devised in view of the above-describedcircumstances and an object thereof is to provide a data carrier systemwhich can reliably record operational data.

DISCLOSURE OF THE INVENTION

A data carrier system described in claim 1 is characterized bycomprising: a vehicle-side control device installed in a vehicle andtransmitting operational data of the vehicle; and a receiving device forreceiving operational data transmitted from the vehicle-side controldevice, wherein the receiving device includes a storage portion whichstores received operational data, and said vehicle-side control deviceincludes: a storage capacity detecting portion for detecting the storagecapacity of said storage portion and an initialization detecting portionfor detecting that said storage portion is initialized, and when thestorage capacity of said storage portion is in a full state, thevehicle-side control device writes operational data in a storage portionof its own, and when said storage portion is initialized, thevehicle-side control device writes the operational data stored in thestorage portion of its own in the storage portion of said receivingdevice.

According to the above-described means, when the storage capacity of thereceiving device becomes full, the vehicle-side control device writesoperational data in a storage portion of its own, and when the receivingdevice is initialized, the vehicle-side control device writes the storedoperational data in the receiving device. For this reason, even when thestorage capacity of the receiving device becomes full, the operationaldata is stored. Accordingly, even in the situation in which it isdifficult to perform initialization of the receiving device carried intoan office or the like, the operational data is reliably recorded.

A data carrier system described in claim 2 is characterized in that thevehicle-side control device includes a notifying portion which indicatesthat operational data is written in the storage portion of thevehicle-side control device.

According to the above-described means, the state in which operationaldata is written in the vehicle-side control device is notified. For thisreason, the state in which the storage capacity of the receiving deviceis in a full state is indirectly notified, and therefore, a driver isrequired to perform initialization of the receiving device.

A data carrier system described in claim 3 is characterized in that thevehicle-side control device includes a notifying portion which indicatesthat the operational data stored in the storage portion of its own isbeing written in the storage portion of the receiving device.

According to the above-described means, the state in which theoperational data stored in the vehicle-side control device is written inthe receiving device is notified. For this reason, there is preventedsuch a situation that the communication between the vehicle-side controldevice and the receiving device is interrupted during writing ofoperational data and the writing of operational data is thereby impeded.

A data carrier system described in claim 4 is characterized bycomprising: a vehicle-side control device installed in a vehicle andtransmitting operational data of the vehicle; and a receiving device forreceiving operational data transmitted from the vehicle-side controldevice, wherein the receiving device includes a storage portion whichstores received operational data, and said vehicle-side control deviceincludes: a remaining storage capacity detecting portion which detectsthe remaining storage capacity of said storage portion; and a notifyingportion which indicates a result of detection of the remaining storagecapacity.

According to the above-described means, the vehicle-side control devicedetects the remaining storage capacity of the receiving device andindicates the detection result. For this reason, it is possible for adriver to easily perform management in which the receiving device isinitialized in a state of being carried into an office or the like, andtherefore, the operational data is reliably recorded.

A data carrier system described in claim 5 is characterized in that whenthe result of detection of the remaining storage capacity is lower thana predetermined value, the vehicle-side control device indicates theresult of detection. According to the above-described means, when theremaining storage capacity of the receiving device is lower than thepredetermined value, the result of detection of the remaining storagecapacity is notified. For this reason, there is prevented such asituation that the driver receives useless information in that theremaining storage capacity is large, so as to induce inadvertentattention.

A data carrier system described in claim 6 is characterized in that thenotifying portion is comprised of a light source whose lighted statechanges in accordance with the remaining storage capacity.

According to the above-described means, a lighted state of the lightsource changes in accordance with the remaining storage capacity of thereceiving device, and therefore, the remaining storage capacity can benotified relatively roughly.

A data carrier system described in claim 7 is characterized in that thenotifying portion is comprised of a display portion which displays theremaining storage capacity in a numeric or graphic display.

According to the above-described means, the remaining storage capacityof the receiving device is displayed in a numeric or a graphic manner,and therefore, the remaining storage capacity can be notified relativelyexactly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are of diagrams which shows a first embodiment of thepresent invention (a flow chart which shows the contents of control madeto allow recording of operational data by a vehicle-side controller).

FIGS. 2A and 2B are diagrams flow charts which show the contents ofcontrol made to correct a data length by a control circuit at the sideof a vehicle, a control circuit at the side of an R/W device, and acontrol circuit at the side of a key.

FIG. 3 is a diagram which shows the relationship between a clockfrequency of a transponder and a communication enable range.

FIG. 4 is a diagram which shows the state of communication of databetween a personal computer, an R/W device, and a transponder.

FIG. 5 is a diagram which schematically shows an overall structure.

FIG. 6 is a diagram which shows an electrical structure of an R/Wdevice.

FIG. 7 is a side view which shows the R/W device in a partially brokenstate.

FIG. 8 is a top view which shows the R/W device.

FIG. 9 is a side view which shows the R/W device.

FIG. 10 is a diagram which shows an electrical structure of atransponder.

FIG. 11 is a diagram which shows data layout of a nonvolatile memory.

FIG. 12 is a diagram which shows an electrical structure of avehicle-side controller.

FIG. 13 is a diagram which shows an outside of the vehicle-sidecontroller.

FIG. 14 is diagrams which each show a communication waveform of thevehicle-side controller, the key, and the R/W device.

FIG. 15 is diagrams which each show an image surface of a personalcomputer.

FIG. 16 is diagrams which each show an image surface of the personalcomputer.

FIG. 17 is a diagram which shows an image surface of the personalcomputer.

FIG. 18 is diagrams which each show an image surface of the personalcomputer.

FIG. 19 is a diagram which shows an image surface of the personalcomputer.

FIG. 20 is a diagram which shows an image surface of the personalcomputer.

FIG. 21 is a diagram which shows an image surface of the personalcomputer.

FIG. 22 is a diagram which shows an image surface of the personalcomputer.

FIG. 23 is diagrams which each show an image surface of the personalcomputer.

FIG. 24 is a diagram which shows an image surface of the personalcomputer.

FIG. 25 is a diagram which shows an image surface of the personalcomputer.

FIG. 26 is a diagram showing a second embodiment of the presentinvention, which corresponds to FIG. 1.

FIG. 27 is a diagram showing a conventional example.

EMBODIMENTS

A first embodiment of the present invention will be hereinafterdescribed with reference to FIGS. 1 to 25. First, in FIG. 5, aconstruction vehicle 11 is equipped with a vehicle-side controller 12corresponding to a vehicle-side control device. As shown in FIG. 12, thevehicle-side controller 12 includes a control circuit 13 having as amain body a microcomputer, a power amplifier 14, a detection circuit 15,an amplifier 16, two antenna coils 17 a (only one is shown in thedrawing), and two resonant capacitors 17 b (only one is shown in thedrawing). One antenna coil 17 a is provided in an ignition key cylinder(not shown) and the other antenna coil 17 a is provided in a door keycylinder (not shown).

Reference numeral 17 designates a resonant circuit comprised of theantenna coils 17 a and the resonant capacitors 17 b. Further, thecontrol circuit 13 corresponds to a storage capacity detecting portion,an initialization detecting portion, and a remaining storage capacitydetecting portion.

The control circuit 13, the power amplifier 14, the detection circuit15, the amplifier 16, and the two resonant capacitors 17 b areaccommodated in a box 18 (see FIG. 13). As shown in FIG. 13, mounted onthe front surface of the box 18 are mode switches 18 a to 18 e, a setswitch 18 f, two digit switches 18 g, LEDs 18 a 1 to 18 e 1corresponding to a notifying portion and a light source, and an LED 18h. The control circuit 13 effects setting of functions in accordancewith the contents of operation of each of the switches 18 a to 18 g, aswill be described later. The control circuit 13 lights or turns on andoff the LEDs 18 a 1 to 18 e 1 and 18 h, so as to indicate setting statesof functions.

Meanwhile, a power circuit 13 b and an input interface 13 c areaccommodated within the box 18 as shown in FIG. 12 and a power source issupplied from an on-vehicle battery 11 c to the control circuit 13 viathe power circuit 13 b. Further, various on-vehicle sensors 11 d (analternator, a vehicle-speed sensor, a brake switch, and the like) areconnected to the input interface 13 c and the control circuit 13 readsinformation of the various sensors via the input interface 13 c.

As shown in FIG. 5, a regular key 19A and a master key 19B are eachformed of a main body portion 19 a and a key grip 19 b, and atransponder 20 is provided in each key grip 19 b. Each transponder 20corresponds to a receiving device. As shown in FIG. 10, the transponder20 includes a resonant circuit 21, a power circuit 22, a control circuit23, a reset circuit 24, a CR oscillation circuit 25, a nonvolatilememory 26 (corresponding to a storage portion) comprised of EEPROM, adetection circuit 27, and a modulation circuit 28.

Meanwhile, the regular key 19A is a key carried by a driver for thepurpose of driving, and the master key 19B is a key exclusively used forregistering an ID code and the like.

The resonant circuit 21 is comprised of an antenna coil 21 a and aresonant capacitor 21 b. When the main body portion 19 a of the key 19Aor 19B is inserted in the ignition key cylinder or in the door keycylinder, the antenna coil 17 a at the side of the vehicle and theantenna coil 21 a of the resonant circuit 21 are electromagneticallyconnected in a non-contacting state.

The vehicle-side control circuit 13 stores a control program, andaccompanying an on/off operation of the power amplifier 14 based on thecontrol program, the control circuit 13 transmits a power signal (acarrier signal shown in FIG. 14a), a level of which decreases with apredetermined timing, from each antenna coil 17 a.

Accordingly, in a state in which the main body portion 19 a of the key19A or 19B is inserted in the ignition key cylinder or in the door keycylinder and the vehicle-side antenna coil 17 a and the key-side antennacoil 21 a are electromagnetically connected, the power signaltransmitted from the vehicle-side antenna coil 17 a is supplied to thekey-side antenna coil 21 a in a non-contacting state. Meanwhile, theresonance frequency of the resonant circuit 21 is set to be equal to afrequency band of the power signal transmitted from the side of thevehicle.

The power circuit 22 is comprised of a rectifying diode 22 a, a diode 22b for a constant voltage, a smoothing capacitor 22 c, a constant-voltagecircuit 22 d, and the like, and produces a direct-current power sourceby rectifying and smoothing the power signal received by the key-sideantenna coil 21 a. Further, the control circuit 23 is mainly comprisedof a microcomputer. The direct current power source formed by the powercircuit 22 is supplied to a power terminal VDD of the control circuit 23and the control circuit 23 is driven by the direct-current power sourcefrom the power circuit 22.

The reset circuit 24 is comprised of a diode 24 a and a capacitor 24 b,and until the direct-current power source supplied to the power terminalVDD reaches a predetermined level, the control circuit 23 is held in apower-on reset state. Further, the CR oscillation circuit 25 iscomprised of a resistance 25 a and a capacitor 25 b and determines aclock frequency of the control circuit 23.

Addresses 0 to 2047 (8-bit×2,048 addresses) of the nonvolatile memory 26are, as shown in FIG. 11, divided into pages 0 to 15 (the numbersindicated at a left end side of the drawing are boundary addresses ofpages 0 to 15). The pages 0 to 15 are divided into an operational dataarea in which operational data is written and a user data area in whichuser data such as optional carrying data is written. Addresses 0 to 31of the operational data area are provided as a system area and an IDcode is in advance recorded in the system area.

Meanwhile, the operational data and the user data each correspond tovehicle data. Further, the system area also stores, in addition to theID code, the following key information (each key information will bedescribed later): system code; password; setting information for anoperational data area password; setting information for a user data areapassword; setting information for user data area write protect, areasetting information, a recording start page; and an R/W update counter.

The detection circuit 27 is, as shown in FIG. 10, comprised of adetecting diode 27 a, a capacitor 27 b, and the like. The detectioncircuit 27 shapes the power signal received by the key-side antenna coil21 a, and further, removes noise from the power signal and supplies itto the key-side control circuit 23. FIG. 14(a) shows the power signal tobe supplied from the detection circuit 27 to the control circuit 23.

As shown in the same figure, the key-side control circuit 23 startsreading data based on detection of Start Of Message (=4To), and makes adetermination about the contents of data transmitted from thevehicle-side control circuit 13 based on a combination of data 1 (=2To)and data 0 (=To). Then, based on the result of this determination, thecontrol circuit 23 reads the user data from the user data area of thenonvolatile memory 26 or writes operational data in the operational dataarea.

In this case, the key-side control circuit 23 performs addition for acounter based on a clock frequency of the CR oscillation circuit 25, andat the same time, measures a data transmitting time (data length) anddiscriminates SOM (Start Of Message), data 1, and data 0. The range T inwhich SOM can be discriminated is represented by “4To−1.2To<T<4To+1.2To”or thereabouts, the range T in which data 1 can be discriminated isrepresented by “2To−0.6To<T<2To+0.6To” or thereabouts, and the range Tin which data 0 can be discriminated is represented by“To−0.3To<T<To+0.3To” or thereabouts (allowance is ±30% or thereabouts).

Meanwhile, a time constant of the detection circuit 27 allows shaping ofthe power signal, and therefore, it is set to be smaller than that ofthe power circuit 22. Further, in FIG. 14, Δ T corresponds to an offtime of the power amplifier 14 controlled by the vehicle-side controlcircuit 13.

The modulation circuit 28 is, as shown in FIG. 10, comprised of atransistor 28 a, a resistance 28 b, and the like. The key-side controlcircuit 23 changes an impedance of the resonant circuit 21 by turning onor off the transistor 28 a and responds to the contents of a commandfrom the vehicle-side control circuit 13. As a result, synchronouslywith the change in the impedance of the resonant circuit 21, theamplitude of a response signal (a carrier signal shown in FIG. 14b)received by the vehicle-side antenna coil 17 a changes.

The detection circuit 15 at the side of the vehicle shapes the responsesignal received by the antenna coil 17 a and supplies it to the controlcircuit 13 via the amplifier 16. FIG. 14(b) shows a response signalsupplied to the control circuit 13. As shown in this drawing, when thecontrol circuit 13 detects inputting of SOM after frame synchronization,the control circuit 13 starts reading data and makes a determinationabout the contents of a response from the key-side control circuit 23based on the subsequent response signals.

Next, a preliminary operation for using the vehicle-side controller 12will be described.

[Registration of key (when the master key 19B is used)]

The master key 19B is inserted in the ignition key cylinder. After 10seconds or more have elapsed with a starter switch 11 a (see FIG. 12) ofthe vehicle 11 set in an OFF state, the starter switch 11 a is turned toACC. As a result, the vehicle-side control circuit 13 switches the poweramplifier 14 on or off, and at the same time, transmits a power signalwhich indicates “send an ID code” to the key-side control circuit 23.

When the key-side control circuit 23 receives the power signal, it isactivated to determine the contents of a command of the power signal,and further reads out the ID code from a system area of the nonvolatilememory 26. Then, the control circuit 23 switches the transistor 28 a ofthe modulation circuit 28 on or off, so as to transmit the ID code tothe vehicle-side control circuit 13.

The vehicle-side control circuit 13 has a nonvolatile memory 13 a (seeFIG. 12) comprised of EEPROM and the nonvolatile memory 13 a stores inadvance an ID code of the master key 19B. When the control circuit 13receives the ID code of the master key 19B from the key-side controlcircuit 23, the control circuit 13 reads out the ID code from thenonvolatile memory 13 a and compares it with the ID code received fromthe side of the key. In this case, these ID codes coincide with eachother, and therefore, the control circuit 13 switches the LED 18 a 1 onand off and indicates that the operation has proceeded to a keyregistration mode. The nonvolatile memory 13 a corresponds to a storageportion.

When it is determined that the LED 18 a 1 has been switched on and off,the regular key 19A is inserted in the ignition key cylinder and turnedto ACC within ten seconds after the starter switch 11 a has been turnedto OFF. As a result, the vehicle-side control circuit 13 reads out theID code from the regular key 19A in the above-described procedure andwrites the ID code in the nonvolatile memory 13 a. Then, the controlcircuit 13 turns on the LED 18 a 1 for five seconds, so as to indicatethe registration of the regular key 19A.

When the LED 18 a 1 is turned off, another regular key 19A is insertedin the ignition key cylinder and turned to ACC within ten seconds afterthe starter switch 11 a has been turned to OFF. As a result, thevehicle-side control circuit 13 reads out an ID code from the regularkey 19A in the above-described procedure and writes the ID code in thenonvolatile memory 13 a. Then, the control circuit 13 turns on the LED18 a 1 for five seconds, to thereby indicate registration of thisregular key 19A.

When the above-described registration for all the regular keys 19A hasbeen completed, the starter switch 11 a is turned to START after it isconfirmed that the LED 18 a 1 is turned off. As a result, thevehicle-side control circuit 13 recognizes that the registration of thekeys has been completed, and turns on and off all the LEDs 18 a 1 to 18e 1 and 18 h a plurality of times (for example, twice) so as to indicatecompletion of the registration of the keys. Meanwhile, the maximumnumber of the regular keys 19A which can be registered is three, and twomaster keys 19B are provided.

[Registration of master code]

A master code is required when registration of a key is carried outwithout using the master key 19B, and is registered in the followingprocedure. After the regular key 19A is inserted in the ignition keycylinder and is turned to ACC, the mode switches 18 a to 18 e areselectively operated by pressing five times. Here, the vehicle-sidecontrol circuit 13 stores numerical values 1 to 5 correspondingly to themode switches 18 a to 18 e, and sets the master code in accordance withwhich of the mode switches 18 a to 18 e have been operated. For example,when the mode switches 18 e, 18 d, 18 c, 18 b, and 18 a are operatedsequentially, the master code is set at “54321”.

After the mode switches 18 a to 18 e have been selectively operated fivetimes, the set switch 18 f is continuously pressed for four seconds ormore. As a result, the vehicle-side control circuit 13 makes adetermination that inputting of the master code has been completed, andregisters the master code at “54321”. Then, the control circuit 13 turnsthe LED 18 h on and off a plurality of times (for example, five times)to thereby indicate that the registration of the master code has beencompleted.

[Registration of key (when the master key 19B is not used)]

After the regular key 19A is inserted in the ignition key cylinder andten seconds or more have elapsed with the starter switch 11 a being setin an OFF state, the regular key is turned to ACC and the master code isinputted. Inputting of the master code is carried out in the sameprocedure as explained in the section, “registration of a master code”.

As a result, the vehicle-side control circuit 13 turns the LED 18 a 1 onand off and indicates that the process has proceeded to a keyregistration mode. Then, the ID code is read out from the regular key19A in the above-described procedure and is written in the nonvolatilememory so as to be registered. Meanwhile, registration of the second andsubsequent keys is carried out in the same way as in the case of usingthe master key 19B.

[Registration of secret identification code]

A secret identification code is required when a system is stopped due toreasons of loss or failure of a registered key, or other reasons. Thesecret identification code is registered in the following procedure.Meanwhile, stoppage of the system will be described later.

The regular key 19A or the master key 19B is inserted in the ignitionkey cylinder, and an operation set including the following operations(1) and (2) is carried out four times (sets).

(1) the key 19A or 19B is turned in the order of (OFF)→ACC→OFF, only Ntimes (N is an integer of 1 to 9); and

(2) the key 19A or 19B is turned in the order of (OFF)→HEAT→OFF, onlyonce.

For example, when N=1 in a first set, N=2 in a second set, N=3 in athird set, and N=4 in a fourth set, the vehicle-side control circuit 13confirms that the secret identification code is “1234”.

After the secret identification code is inputted, the key 19A or 19B isheld at the position of HEAT for four seconds or more. As a result, thevehicle-side control circuit 13 ends the registration of the secretidentification code “1234” and turns the LED 18 h on and off a pluralityof times (for example, five times), so as to indicate that theregistration of the secret identification code has been completed.

[Setting of internal clock]

An internal clock becomes a reference for detection of operational datasuch as the date and time of a start-up of an engine and is set in thefollowing procedure.

After the starter switch 11 a has been turned to ACC by the regular key19A, the set switch 18 f is continuously pressed for four seconds ormore. As a result, the vehicle-side control circuit 13 turns the LEDs 18a 1 to 18 e 1 and 18 h on and off a plurality of times (for example,three times), and thereafter, the control circuit 13 stops an on-and-offstate of the LED 18 h and holds only the LEDs 18 a 1 to 18 e 1 in anon-and-off state, and indicates that the operation has proceeded to aclock setting mode.

When the set switch 18 f is operated, an operation set including anoperation of the digit switches 18 g and an operation of the set switch18 f is effected five times (sets), and simultaneously, the year, month,date, time, and minute are sequentially inputted. As a result, thevehicle-side control circuit 13 sets, based on an output signal from thedigit switches 18 g, the year, month, date, time, and minute of theinternal clock. At the same time, the LEDs 18 a 1 to 18 e 1 aresequentially turned off each time setting of the year, month, date,time, and minute is completed. Then, the control circuit 13 turns theLEDs 18 a 1 to 18 e 1 and 18 f on and off a plurality of times (forexample, twice) to thereby indicates completion of setting the internalclock.

Meanwhile, in performing “registration of master code”, “registration ofsecret identification code”, and “setting of internal clock”, when thestarter switch 11 a is turned to ACC, the vehicle-side control circuit13 transmits to the key-side control circuit 23 a power signal whichcommands to “send an ID code”. As a result, the key-side control circuit23 reads out the ID code from the system area of the nonvolatile memory26 and transmits the ID code to the vehicle-side control circuit 13.

When the vehicle-side control circuit 13 receives the ID code, it readsout the registered ID code from the nonvolatile memory 13 a and comparesthe same with an ID code from the key side. Here, only when the ID codefrom the key side exists among the read ID codes, are “registration ofmaster code”, “registration of secret identification code”, and “settingof internal clock” allowed.

[Assignment of operation mode to mode switches]

The mode switches 18 a to 18 e are used to allow the vehicle-sidecontrol circuit 13 to recognize which operation is being effected atpresent (for example, when operation of mode 1 is effected, the modeswitch 18 a is operated, reporting to the control circuit 13 that theoperation of a mode 1 is being effected). It is preferable that anassigned operation mode be clearly shown in the vicinity of the modeswitches 18 a to 18 e so as to prevent malfunction of the mode switches18 a to 18 e.

Next, functions of the vehicle-side controller 12 will be described.

[Door security function]

After the regular key 19A has been inserted in the door key cylinder andturned to the right side (i.e., the side of locking) or to the left side(i.e., the side of lock release), the regular key 19A is turned back toan original position. As a result, the vehicle-side control circuit 13transmits a power signal which indicates, “transmit ID code”, to thekey-side control circuit 23 and it is determined by the control circuit13 whether the ID code received from the key-side control circuit 23 hasbeen registered. For example, when the ID code from the key side hasbeen registered, a lever disposed at a back side of the door keycylinder and a door locking mechanism are linked together so that a dooris brought into an unlockable state. Accordingly, in this state, whenthe regular key 19A is turned to the left side (i.e., the side of lockrelease), the door is unlocked.

Further, when the ID code from the key side is not registered, thevehicle-side control circuit 13 records in the nonvolatile memory 13 athe fact that there is abnormality in the security aspect. At the sametime, the control circuit 13 effects an operation for causing a horn(not shown) of the vehicle 11 to make a sound for a predetermined time(for example, 30 seconds) and an operation for turning on and off alight (not shown) of the vehicle 11 for a predetermined time (forexample, 4 minutes), to thereby indicate that there was abnormality inthe security aspect. Meanwhile, in FIG. 12, reference numeral 11 bdesignates a door switch, which is turned on together with rotation ofthe door key cylinder. The vehicle-side control circuit 13 detects,based on an on signal from the door switch 11 b, that the regular key19A has been turned.

[Immobilizer function]

The regular key 19A is inserted in the ignition key cylinder and isturned to ACC or to HEAT. As a result, the vehicle-side control circuit13 transmits to the key-side control circuit 23 a power signal whichindicates, “transmit ID code”, and it is determined by the controlcircuit 13 whether the ID code received from the key-side controlcircuit 23 has been registered.

For example, when the ID code from the key side has been registered, thevehicle-side control circuit 13 turns on a main power source of thevehicle 11 to allow the start-up of the engine. Further, when the IDcode from the key side has not been registered, the vehicle-side controlcircuit 13 records in the nonvolatile memory 13 a the fact that therewas abnormality in the security aspect. At the same time, the controlcircuit 13 effects the operation for causing the horn to make a soundand the operation for turning the light on and off, to thereby indicatethat there was abnormality in the security aspect.

Meanwhile, when the vehicle-side control circuit 13 detects any one ofthe following operations (1) and (2), the control circuit 13 stopscausing the horn to make a sound and turning the light on and off.

(1) The registered regular key 19A or the registered master key 19B isused to turn the starter switch 11 a to HEAT or to ACC.

(2) The registered regular key 19A or the registered master key 19B isused to turn the door switch 11 b (to either of the right and leftsides).

[Operational data recording function]

When the engine is started, the vehicle-side control circuit 13transmits, to the key-side control circuit 23, a power signal whichindicates, “record operational data”, and a power signal which indicatesthe “date and time of the start-up of the engine”. As a result, thekey-side control circuit 23 writes the date and time of the start-up ofthe engine in the operational data area of the nonvolatile memory 26. Inthis case, the system area is provided in a beginning portion of theoperational data area, and therefore, writing of the operational data isexecuted with the 32-th address of page 0 set as a top address.

When the engine is started, the vehicle-side control circuit 13 measureson-time T1 to T5 of the mode switches 18 a to 18 e and an off-time T0 inwhich none of the mode switches 18 a to 18 e is turned on.

For example, when the mode switch 18 a corresponding to the mode 1 isoperated, the vehicle-side control circuit 13 performs addition for anoperating time counter 1, so as to measure the operating time T1 of themode 1. In this state, when the mode switch 18 b corresponding to anoperation mode 2 is operated, the control circuit 13 performs additionfor an operating time counter 2, so as to measure the operating time T2of the operation mode 2. When the vehicle-side control circuit 13measures the on-time T1 to T5 and the off-time T0, it transmits theoperation mode to the key-side control circuit 23 at six-minuteintervals and records the operation mode (see FIG. 17) for each unit oftime. The operation mode having the longest operating time during theinterval of six minutes is transmitted. For example, when the on-time ofthe mode switch 18 a is one minute, the on-time of the mode switch 18 bis two minutes, and the on-time of the mode switch 18 c is threeminutes, the control circuit 13 transmits that the operation mode of sixminutes is “mode 3” corresponding to the mode switch 18 c. Meanwhile,when the off-time T0 is the longest, “mode 0” is transmitted.

FIG. 1 is a flow chart which shows the contents of control performed bythe vehicle-side control circuit 13 to record operational data. Here,when the engine is started, the process proceeds to step S21 and thevehicle-side control circuit 13 reads, from the key-side control circuit23, the storage capacity of the nonvolatile memory 26 (the storagecapacity of an operational data area) and a value of an R/W updatecounter.

The R/W update counter performs addition by one (“1”) each time theoperational data area of the nonvolatile memory 26 is initialized (see“reading function of key information”). When the vehicle-side controlcircuit 13 reads the value of the R/W update counter, the processproceeds to step S22, in which it is determined whether the value of theR/W update counter coincides with a value read at a previous time. Forexample, when a present value and a previous value of the R/W updatecounter coincide with each other, it is determined that the operationaldata area has not been initialized, and the process proceeds from stepS22 to step S23.

The vehicle-side control circuit 13 records a writing start address A ofoperational data for the key-side nonvolatile memory 26 in a memory(RAM) of its own (step S25). When the process proceeds to step S23, itis determined whether, based on the storage capacity of the operationaldata area detected in step S21 and the address A, “the storage capacityof the key-side nonvolatile memory 26 (the storage capacity of theoperational data area) is in a full state”.

For example, when the storage capacity of the operational data area isnot in a full state, the process proceeds from step S23 to step S24 andthe vehicle-side control circuit 13 writes operational data in theoperational data area with the writing start address A is set at thehead. Then, the process proceeds to step S25, in which the vehicle-sidecontrol circuit 13 updates the writing start address A and writes in thememory (RAM) of its own.

Further, when in step S23 it is determined that “the storage capacity ofthe key-side nonvolatile memory 26 (the storage capacity of theoperational data area) is in a full state”, the process proceeds fromstep S23 to step S26 in which the vehicle-side control circuit 13 writesthe operational data in the nonvolatile memory 13 a of its own, and theprocess proceeds to step S27.

Meanwhile, the operational data area is provided in the vehicle-sidenonvolatile memory 13 a and the vehicle-side control circuit 13 writesoperational data in the operational data area. Further, the vehicle-sidecontrol circuit 13 records, in the memory (RAM) of its own, a writingstart address B of operational data for the operational data area of itsown (step S27). When the process proceeds to step S26, the controlcircuit 13 writes operational data with the address B set at the head.

When the process proceeds to step S27, the vehicle-side control circuit13 updates a writing start address B at the side of the vehicle andwrites the same in the memory (RAM) of its own. Then, the processproceeds to step S28 and the control circuit 13 turns on and off the LED18 a 1, so as to indicate that operational data is recorded in thevehicle-side nonvolatile memory 13 a (i.e., the storage capacity of theoperational data area at the key side is in a full state).

Further, when in step S22 the vehicle-side control circuit 13 detectsthat “the present value and the previous value of the R/W update counterdo not coincide with each other”, it is determined that the key-sideoperational data area has been initialized, and therefore, the processproceeds from step S22 to step S29. Then, it is determined by thevehicle-side control circuit 13 whether the operational data has beenwritten in the nonvolatile memory 13 a owned by the control circuit 13.

For example, when the operational data has not been written in thenonvolatile memory 13 a, the process proceeds from step S29 to step S30and the operational data is written in the key-side nonvolatile memory26 with an initial address set at the head. Then, the process proceedsto step S25 and the control circuit 13 updates the writing start addressA at the key side and records in the memory (RAM) of its own.

Further, when in step S29 it is determined by the vehicle-side controlcircuit 13 that “the operational data is written in the nonvolatilememory 13 a owned by the control circuit 13”, the process proceeds fromstep S29 to step S31 in which operational data is read from thenonvolatile memory 13 a. Then, the process proceeds to step S32 in whichthe operational data is written in the key-side nonvolatile memory 26with the initial address set at the head, and thereafter, the processproceeds to step S33.

When the process proceeds to step S33, the vehicle-side control circuit13 turns on and off the LED 18 b 1, so as to indicate that theoperational data stored in the nonvolatile memory 13 a owned by thecontrol circuit 13 is written in the key-side nonvolatile memory 26.Then, the process proceeds to step S34 in which a writing start addressB at the side of the vehicle is rewritten to “0”, and thereafter, theprocess proceeds to step S25 in which the vehicle-side control circuit13 records the key-side writing start address A in the memory (RAM) ofits own.

[Past history function of security]

The vehicle-side control circuit 13 records, as described above, a pasthistory in terms of the security aspect during stoppage of the engine.When the engine is started, the control circuit 13 reads out the pasthistory in terms of the security aspect from the nonvolatile memory 13 aand transmits a command signal, “record data”, and “past history ofsecurity” data. As a result, the key-side control circuit 23 writes the“past history in terms of the security aspect” in the operational dataarea of the nonvolatile memory 26. Meanwhile, the past history data ofsecurity corresponds to a portion of operational data and is processedin accordance with the flow chart shown in FIG. 1.

[System stopping function]

The regular key 19A or the master key 19B (an unregistered key may alsobe used) is inserted in the starter switch 11 a and the operationdescribed in the section of “registration of secret identification code”is effected, and at the same time, the secret identification code isinputted. As a result, the vehicle-side control circuit 13 stops“operational data recording function”, “immobilizer function”, and “doorsecurity function” and turns the LED 18 h on and off a plurality oftimes (for example, five times), and at the same time, the controlcircuit 13 indicates that the system is down.

Meanwhile, the stoppage of the system is also performed by inserting theregular key 19A or the master key 19B (which may also be an unregisteredkey) in the door key cylinder and by inputting the secret identificationcode. In this case, inputting of the secret identification code isexecuted by turning the key 19A or 19B in the order, of (OFF)→the rightside (the side of locking) →OFF. Further, determination of the inputtingis made in the order of, (OFF)→the left side (the side of lockrelease)→OFF.

[Set-up of system]

When the regular key 19A or the master key 19B (which may also be anunregistered key) is inserted in the starter switch 11 a in asystem-down state and the operation described in the section of“registration of secret identification code” is effected, at the sametime, a secret identification code is inputted. As a result, thevehicle-side control circuit 13 performs set-up of the system.

In the above-described structure, the voltage of the key-side controlcircuit 23 varies under the influence of environmental temperature orthe like by the reason that operating power is supplied from thevehicle-side control circuit 13 to the key-side control circuit 23 in anon-contacting state. As a result, the clock frequency of the key-sidecontrol circuit 23 varies, and therefore, there is a possibility thatdata communication between the vehicle-side control circuit 13 and thekey-side control circuit 23 cannot be accurately performed. Accordingly,when each of the above-described operations is performed, the length ofdata is corrected in such a manner as described below. When the engineis started, the process proceeds to step S1 in FIG. 2 and thevehicle-side control circuit 13 transmits data (a command signal or thelike) to the key-side control circuit 23 at the standard time.

The key-side control circuit 23 performs addition for a counter based onthe clock frequency thereof, and at the same time, measures a datareceiving time (data length) and discriminates SOM, data 1 and data 0.When the key-side control circuit 23 receives data in step S2, theprocess proceeds to step S3 in which it is determined whether the valueof the counter is within a standard range (the above-described range ofallowance ±30%). For example, when the value of the counter is withinthe standard range, the process proceeds from step S3 to step S4 and thecontents of data are determined. Then, the process proceeds from step S4to step S5, and based on the result of this determination, the key-sidecontrol circuit 28 turns on or off the transistor 28 a of the modulationcircuit 28, and at the same time, transmits a response signal to thevehicle-side control circuit 13.

When in step S6 the vehicle-side control circuit 13 receives theresponse signal from the key-side control circuit 23, the vehicle-sidecontrol circuit 13 obtains a central value by averaging framesynchronization, and thereafter, based on the central value, a shearrate of the clock frequency of the key-side control circuit 23 isestimated. Then, the process proceeds from step S6 to step S7 and thecontents of the received signal is determined while considering theshear rate of the clock frequency. Here, the received signal is normaldata (a response to data transmitted to the key-side control circuit23), and therefore, a predetermined processing operation is performedbased on the normal data (end).

When in step S3 it is determined by the key-side control circuit 23 thatthe value of the counter is not within the standard range, it isdetermined that the clock frequency varies. The process proceeds fromstep S3 to step S8 and it is determined whether the value of the counteris greater than the standard.

For example, when the value of the counter is greater than the standard(when the clock frequency of the key-side control circuit 23 is higherthan the standard), the process proceeds from step S8 to step S9 and thekey-side control circuit 23 turns on or off the transistor 28 a of themodulation circuit 28, and at the same time, transmits a “receiving-time(long) error signal” to the vehicle-side control circuit 13. Further,when the value of the counter is less than the standard (when the clockfrequency of the key-side control circuit 23 is lower than thestandard), the process proceeds from step S8 to step S10. The key-sidecontrol circuit 23 turns on or off the transistor 28 a of the modulationcircuit 28, and at the same time, transmits the “receiving-time (short)error signal” to the vehicle-side control circuit 13.

When the vehicle-side control circuit 13 receives the response signalfrom the key-side control circuit 23 in step S6, the vehicle-sidecontrol circuit 13 obtains a central value by averaging framesynchronization, and thereafter, based on the central value, the controlcircuit 13 estimates a shear rate of the clock frequency of the key-sidecontrol circuit 23. Then, the process proceeds from step S6 to step S7and the contents of the received signal is determined while consideringthe shear rate of the clock frequency. Here, since the received data isnot normal data, the process proceeds from step S7 to step S11.

When the process proceeds to step S11, it is determined by thevehicle-side control circuit 13 whether the received signal is the“receiving-time (long) error signal”. For example, when the receivedsignal is the “receiving-time (long) error signal”, the process proceedsfrom step S11 to step S12 and the control circuit 13 retransmitsprevious data to the key-side control circuit 23 at the standard time×K1(<1). Further, when the received signal is not the “receiving-time(long) error time” (when the received signal is the “receiving-time(short) error time”), the process proceeds to step S13 and the controlcircuit 13 retransmits previous data to the key-side control circuit 23at the standard time×K2 (<1).

When data is retransmitted from the vehicle-side control circuit 13 tothe key-side control circuit 23, the above-described series ofoperations are repeated until the data receiving time of the key-sidecontrol circuit 23 reaches the standard range. When the data receivingtime of the key-side control circuit 23 reaches the standard range,normal data is transmitted from the key-side control circuit 23 to thevehicle-side control circuit 13, and therefore, the vehicle-side controlcircuit 23 performs the predetermined processing operation based on thenormal data.

As shown in FIG. 5, a desktop personal computer 30 (hereinafter referredto as a personal computer 30) corresponding to an external controller isinstalled in an office 29. Connected to the personal computer 30 is aread/write device 31 (hereinafter referred to as an R/W device 31)corresponding to a reading device. The R/W device 31 will be hereinafterdescribed in detail.

As shown in FIG. 6, a box 32 includes a power circuit 33 and a controlcircuit 34 mainly comprised of a microcomputer. A jack 32 a (see FIG. 9)and a power switch 32 b (see FIG. 7) are mounted to the box 32. As shownin FIG. 5, after a plug 35 a of an AC adapter 35 is inserted in the jack32 a and a receptacle 35 b of the AC adapter 35 is inserted in acommercial AC power source (not shown), when the power switch 32 b isturned on, a power source is supplied to the control circuit 34 via thepower circuit 33 and the control circuit 34 is thereby driven.

A green indicator lens 32 c is, as shown in FIG. 8, mounted to the box32. As shown in FIG. 6, an LED 36 a is provided within the box 32. Whenthe power switch 32 b is turned on, the control circuit 34 supplies apower source to the LED 36 a. As a result, the indicator lens 32 c islighted to indicate that the power source is on.

A serial interface 37 is provided in the box 32. Further, a connector 32d is, as shown in FIG. 9, mounted to the box 32. As shown in FIG. 5,when a connector 30 b of the personal computer 30 is inserted in theconnector 32 d, the control circuit 34 and the personal computer 30 areconnected via the serial interface 37 so as to allow serialcommunication between the personal computer 30 and the control circuit34.

As shown in FIG. 7, a cylindrical body 38 is provided in the box 32. Thecylindrical body 38 has a rectangular cross sectional configurationwhose one end surface is open and another end surface is closed. One endsurface 38 a of the cylindrical body 38 is, as shown in FIG. 8, exposedto the outside by passing through a top plate of the box 32.

A key detection switch 39 is, as shown in FIG. 7, provided in the box 32and a plunger 39 a of the key detection switch 39 is disposed within thecylindrical body 38. When the main body portion 19 a of the regular key19 or the main body portion 19 a of the master key 19B is inserted fromthe one end surface 38 a (hereinafter referred to as a key insertionopening 38 a) of the cylindrical body 38 into the cylindrical body 38,the plunger 39 a is pressed down by the main body portion 19 a and thekey detection switch 39 is turned on.

An antenna coil 40 a is mounted at one end portion of the cylindricalbody 38, and when the main body portion 19 a of the regular key 19A orthe main body portion 19 a of the master key 19B is inserted into thekey insertion opening 38 a, the antenna coil 40 a and the key-sideantenna coil 21 a are connected electromagnetically in a non-contactingstate. In FIG. 6, reference numeral 40 b designates a resonant capacitorwhich forms, together with the antenna coil 40 a, a resonant circuit 40.

The antenna coil 40 a is, as shown in FIG. 6, connected to the controlcircuit 34 via the power amplifier 41. The control circuit 34 turns thepower amplifier 41 on or off based on a command signal transmitted fromthe personal computer 30 via the serial interface 37, and at the sametime, the control circuit 34 transmits a power signal (a carrier signal)whose level decreases with a predetermined timing from the antenna coil40 a to the key-side antenna coil 21 a.

This power signal is the same as that supplied from the vehicle-sidecontrol circuit 13 to the key-side control circuit 23. As shown in FIG.14(a), the key-side detection circuit 27 shapes the power signalreceived via the antenna coil 21 a and supplies the same to the controlcircuit 23. As a result, the control circuit 23 detects inputting ofSOM, and at the same time, it starts reading data and determines thecontents of a command based on the subsequent power signals. Then, thecontrol circuit 23 turns the transistor 28 a of the modulation circuit28 on or off, and at the same time, transmits a response signal from theantenna coil 21 a to the antenna coil 40 a at the side of the R/Wdevice.

As shown in FIG. 6, a detection circuit 42 and an amplifier 43 areprovided in the box 32. The detection circuit 42 shapes the responsesignal received by the antenna coil 40 a and supplies the same to thecontrol circuit 34 via the amplifier 43. The response signal is the sameas that transmitted from the key-side control circuit 23 to thevehicle-side control circuit 13. As shown in FIG. 14(b), after framesynchronization, the control circuit 34 at the side of the R/W devicedetects inputting of SOM, and at the same time, starts reading theresponse signal and determines the contents of a response based on thesubsequent response signals.

As shown in FIG. 8, a red indicator lens 32 d is mounted to the box 32.Further, as shown in FIG. 6, an LED 36 b is also provided in the box 32.The control circuit 34 at the side of the R/W device supplies a powersource to the LED 36 b, and at the same time, lights the indicator lens32 d to indicate communication between the R/W device 31 and the key 19A(or 19B).

Next, functions of the R/W device 31 will be described.

[Read/storage function of operational data]

After the power switch 32 b of the R/W device 31 is turned on and themain body portion 19 a of the regular key 19A is inserted into the keyinsertion opening 38 a, when the personal computer 30 is activated, thepersonal computer 30 displays, on a display device 30 a (see FIG. 5), anoperational data management key 44 a, a key information setting key 44b, a user data management key 44 c, and a termination key 44 d, whichare shown in FIG. 15(a). Here, when the operational data management key44 a is clicked, as shown in FIG. 15(b), a data reading key 45 a, anaccumulation processing key 45 b, and a termination key 45 c aredisplayed.

When the data reading key 45 a is clicked in the above-described state,the personal computer 30 gives a command signal to “detect the presenceor absence of a key” to the control circuit 34 at the side of the R/Wdevice. As a result, the control circuit 34 at the side of the R/Wdevice determines, based on an output signal from the key detectionswitch 39, whether there is a key, and transmits the result of thisdetermination to the personal computer 30.

For example, when it is determined that there is no key, the personalcomputer 30 displays a message on the display device 30 a and requiresinsertion of the regular key 19A. Further, when it is determined thatthere is a key, the personal computer 30 transmits a command signal to“read an ID code” to the control circuit 34 at the side of the R/Wdevice.

When the control circuit 34 at the side of the R/W device receives thecommand signal, the control circuit 34 turns the power amplifier 41 onor off, and simultaneously, transmits a power signal which indicates,“transmit an ID code”, from the antenna coil 40 a to the key-sidecontrol circuit 23 via the key-side antenna coil 21 a.

When the key-side control circuit 23 receives the power signal, it isactivated and determines the contents of a command of the power signal.Then, when the control circuit 23 determines the command contentsindicating, “transmit an ID code”, it reads out an ID code from thesystem area of the nonvolatile memory 26 and turns the transistor 28 aof the modulation circuit 28 on or off based on the ID code, andsimultaneously, transmits the ID code to the control circuit 34 at theside of the R/W device.

When the control circuit 34 at the side of the R/W device receives theID code, the control circuit 34 transmits the same to the personalcomputer 30. As a result, as shown in FIG. 16(a), the personal computer30 displays a confirmation message 46 a which indicates, “operationaldata of A12345 (ID code) is read”, an OK key 46 b, a key alteration key46 c, and a cancel key 46 d.

Here, when the cancel key 46 d is clicked, the personal computer 30cancels reading of operational data and returns the image surface to aprevious state. Further, when the key alteration key 46 c is clicked,the personal computer 30 gives a command signal to “read ID code” to thecontrol circuit 34 at the side of the R/W device, repeats theabove-described series of operations, and simultaneously, reads an IDcode of the key 19A newly inserted into the key insertion opening 38 a,and rewrites the confirmation message 46 a based on the ID code.

Further, when the OK key 46 b is clicked, the personal computer 30 givesa command signal to “read operational data” to the control circuit 34 atthe side of the R/W device. As a result, the control circuit 34 at theside of the R/W device gives a power signal which indicates, “transmitoperational data”, to the key-side control circuit 23.

When the key-side control circuit 23 receives the power signal, thecontrol circuit 23 is activated and determines the contents of a commandof the power signal. Then, the control circuit 23 reads operational datafrom the operational data area of the nonvolatile memory 26, and basedon the operational data, turns the transistor 28 a of the modulationcircuit 28 on or off; simultaneously, the control circuit 23 transmitsthe operational data to the control circuit 34 at the side of the R/Wdevice. As a result, the control circuit 34 at the side of the R/Wdevice receives the operational data and transfers the same to thepersonal computer 30.

During communication of the operational data between the personalcomputer 30 and the control circuit 34 at the side of the R/W device, asshown in FIG. 16(b), the personal computer 30 displays a message 47 awhich indicates, “data is being read”, a graph 47 b, and a cancel key 47c, and also indicates the percentage of completion of communication byvarying a longitudinal dimension H of the graph 47 b. Meanwhile, in FIG.16(b), when the cancel key 47 c is clicked, the personal computer 30stops reading the operational data and returns the image surface to thestate shown in FIG. 15(b).

When the communication of the operational data has been completed, asshown in FIG. 17, the personal computer 30 displays operational data 48a, a storage key 48 b, and a termination key 48 c. Here, when thetermination key 48 c is clicked, processing ends. The operational data48 a is comprised of the date, time, operating mode, recording ofabnormalities, and security, and indicates, “the engine was started at12:00 on July 1”, “an operation of the mode 1 was effected from 12:06 to12:24 on July 1 (the contents of operation per unit of time)”, and thelike.

Further, when the storage key 48 b is clicked in FIG. 17, the personalcomputer 30 displays a message 49 a which indicates, “data of a key isstored in a file”, an OK key 49 b, a cancel key 49 c, and a check boss49 d, as shown in FIG. 18(a).

Here, when the check boss 49 d and the OK key 49 b are sequentiallyclicked, the personal computer 30 writes the operational data 48 a in anexternal storage medium 30 c (a floppy disk or a hard disk) shown inFIG. 5 so as to correspond to an ID code. Simultaneously, the personalcomputer 30 gives a command signal which indicates, “give a command toclear operational data”, to the control circuit 34 at the side of theR/W device. As a result, the control circuit 34 at the side of the R/Wdevice gives to the key-side control circuit 23 a command signal to“clear operational data”, so that the key-side control circuit 23 clears(initializes) the operational data written in the operational data areaof the nonvolatile memory 26.

Further, in FIG. 18(a), when the OK key 49 b is directly clicked, thepersonal computer 30 writes the operational data 48 a in the externalstorage medium 30 c without clearing the operational data of thenonvolatile memory 26 at the side of the key. when the cancel key 49 cis clicked, the personal computer 30 returns the image surface to aprevious state.

When the operational data 48 a is stored in the external storage medium30 c, as shown in FIG. 18(b), the personal computer 30 displays amessage 50 a which indicates, “data has been stored in a file”, an OKkey 50 b, and a file title 50 c. Here, when the OK key 50 b is clicked,processing ends. The file title 50 c is prepared by the personalcomputer 30. “A” represents the dominical year (for example, the year1996, 1997, . . . , 2021 are indicated by A, B, . . . , Z,respectively), “2” represents the month, and “A12345” is an ID code ofthe key.

[Accumulation processing function of operational data]

In FIG. 15(b), when the accumulation processing key 45 b is clicked, thepersonal computer 30 displays an accumulation processing list 51 a, anID code input portion 51 b, a year input portion 51 c, a month inputportion 51 d, an OK key 51 e, and a termination key 51 f, which areshown in FIG. 19. Here, when the termination key 51 f is clicked,processing ends.

Further, after the ID code, the year, and the month are respectivelyinputted to the ID code input portion 51 b, the year input portion 51 c,and the month input portion 51 d, when the OK key 51 e is clicked, thepersonal computer 30 reads out the operational data corresponding to theinputted ID code, year, and month from the external storage medium 30 c.Then, the personal computer 30 processes the operational data based onan accumulation processing program and accumulates operational data foreach key (each ID code), for each month, and for each contents ofoperation, and as shown in FIG. 20, the personal computer 30 writes aprocessing result in a predetermined section of the accumulationprocessing list 51 a. Meanwhile, this accumulation processing isexecuted by the personal computer 30 individually, and the R/W device 31does not need to be connected thereto.

[Key information reading function]

In FIG. 15(a), when the key information setting key 44 b is clicked, thepersonal computer 30 gives a command signal to “read key information” tothe control circuit 34 at the side of the R/W device. As a result, thecontrol circuit 34 at the side of the R/W device transmits a commandsignal which indicates, “send key information”, to the key-side controlcircuit 23.

When the key-side control circuit 23 receives the command signal, thecontrol circuit 23 is activated to read out key information from thesystem area of the nonvolatile memory 26, and also transmits the same tothe personal computer 30 via the control circuit 34 at the side of theR/W device. As a result, as shown in FIG. 21, the personal computer 30displays an ID code 52 a as the key information, a next recording startpage 52 b, and an R/W update counter 52 c. Simultaneously, the personalcomputer 30 displays check bosses 52 d 1 to 52 f 2, a final page inputportion 52 g, a key-writing key 52 h, a key information reading key 52i, and a termination key 52 j.

The next recording start page indicates a reading start page ofoperational data for the key-side nonvolatile memory 26. When the nextrecording start page is page 3, the control circuit 34 at the side ofthe R/W device is provided to read and write the operational data withpage 3 set as the start page. Further, the final page input portion 52 gis used to change a boundary between the operational data area and theuser data area. In FIG. 11, the boundary is page 13. Further, the R/Wupdate counter shown in FIG. 21 is used to perform addition whenoperational data is read out from the key 19A and is deleted, andindicates a past history of initialization.

[Key information alteration function 1]

The check bosses 52 d 1 and 52 d 2 shown in FIG. 21 are used to selectwhether a password is used in reading operational data from theoperational data area of the nonvolatile memory 26. When the password isused, the check boss 52 d 1 is clicked, and as shown in FIG. 22, theoperational data area password is switched to being necessary, andthereafter, the key-writing key 52 h is clicked.

The check bosses 52 e 1 and 52 e 2 shown in FIG. 21 are used to selectwhether a password is used in reading user data from the user data areaof the nonvolatile memory 26. When the password is used, the check boss52 e 1 is clicked, and as shown in FIG. 22, the user data area passwordis switched to being necessary, and thereafter, the key-writing key 52 his clicked.

Further, the check bosses 52 f 1 and 52 f 2 shown in FIG. 21 are used toselect whether the user data area is set in a rewritable state. When theuser data area is set in a non-rewritable state, the check boss 52 f 1is clicked, and as shown in FIG. 22, the user data area write protect isswitched to being necessary, and thereafter, the key-writing key 52 h isclicked.

When the key-writing key 52 h is clicked, as shown in FIG. 23(a), thepersonal computer 30 displays a message 53 a which indicates, “Systemcode is needed. Input system code.”, an OK key 53 b, a cancel key 53 c,and a system code input portion 53 d. Here, when the cancel key 53 c isclicked, the image surface is returned to a previous state.

Further, when the OK key 53 b is clicked after a system code (sixalphanumeric characters or less) has been inputted to the system codeinput portion 53 d, the personal computer 30 gives a command to thekey-side control circuit 23 via the control circuit 34 at the side ofthe R/W device; at the same time, the personal computer 30 switches theoperating mode to a mode for reading operational data using a password,a mode for reading user data using a password, or a mode by whichrewriting of the user data area is made impossible.

When the mode is switched, as shown in FIG. 23(b), the personal computer30 displays a message 54 a which indicates, “the following writing hasbeen completed”, switching contents 54 b of modes of “area setting,operational data password setting, user data area password setting, andwriting protect setting”, and an OK key 54 c. Here, when the OK key 54 cis clicked, processing ends.

[Key information alteration function 2]

In FIG. 21, after numeric character N (1 to 15) has been inputted intothe final page input portion 52 g, when the key-writing key 52 h isclicked, the personal computer 30 displays the message 53 a, the OK key53 b, the cancel key 53 c, and the system code input portion 53 d, aswill be shown in FIG. 23(a).

Here, when the OK key 53 b is clicked after a system code has beeninputted into the system code input portion 53 d, the personal computer30 gives a command to the key-side control circuit 23 via the controlcircuit 34 at the side of the R/W device; at the same time, the personalcomputer 30 sets the input value N on the final page of the operationaldata area and sets an input value N+1 on the start page of the user dataarea, and as shown in FIG. 23(b), the personal computer 30 displays themessage 54 a, the mode switching contents 54 b, and the OK key 54 c. InFIG. 1, the storage capacity of the operational data area is detectedserially by the reason that the size of an operational data area changesas described above.

[Key information alteration function 3]

When a password alteration key 55 a is clicked in FIG. 24, as shown inFIG. 23(a), the personal computer 30 displays the message 53 a, the OKkey 53 b, the cancel key 53 c, and the system code input portion 53 d.When the OK key 53 b is clicked after a system code has been inputted tothe system code input portion 53 d, the personal computer 30 displays apassword input portion 56 a and displays a present password (PASS) inthe input portion 56 a, as shown in FIG. 25.

In the above-described state, when the key-writing key 52 h is clickedafter an alteration password has been inputted to the password inputportion 56 a, as shown in FIG. 23(a), the personal computer 30 displaysthe message 53 a, the OK key 53 b, the cancel key 53 c, and the systemcode input portion 53 d. Here, when the OK key 53 b is clicked after asystem code has been inputted to the system code input portion 53 d, thepersonal computer 30 gives a command to the key-side control circuit 23via the control circuit 34 at the side of the R/W device and also altersthe password. Then, as shown in FIG. 23(b), the personal computer 30displays the message 54 a, the mode switching contents 54 b, and the OKkey 54 c.

[Key information alteration function 4]

In FIG. 15(a), when the user data management key 44 c is clicked, thepersonal computer 30 reads out an ID code from the regular key 19A, andalso displays the confirmation message 46 a (which is, in this case, amessage indicating that “user data of A12345 is read”), the OK key 46 b,the key alteration key 46 c, and the cancel key 46 d, as shown in FIG.16(a). Here, when the OK key 46 b is clicked, the personal computer 30reads out user data from the user data area of the nonvolatile memory 26of the key-side control circuit 23 via the control circuit 34 at theside of the R/W device, and also displays the same on the image surface.

Meanwhile, when the operating mode is switched to the mode for readinguser data using a password, the personal computer 30 displays an imagesurface for input of the password. Then, when the personal computer 30detects that the password has been accurately inputted, the personalcomputer 30 reads out the user data from the nonvolatile memory 26 anddisplays the same on the image surface.

Here, when user data (corresponding to user information) such as an IDcode, an engine number, optional carrying data, maintenance data in adealer, a past history of fueling, diagnosis data at the time of use,and the like are inputted to the personal computer 30, the personalcomputer 30 displays the message 53 a, the OK key 53 b, the cancel key53 c, and the system code input portion 53 d, as shown in FIG. 23(a).

Meanwhile, when the operation is switched to the mode by which rewritingof a user data area is made impossible, the personal computer 30displays a message on the image surface and indicates that user datacannot be written.

In FIG. 23(a), when the OK key 53 b is clicked after a system code hasbeen inputted to the system code input portion 53 d, the personalcomputer 30 writes user data in the user data area of the nonvolatilememory 26 via the control circuit 34 at the side of the R/W device orrewrites the user data; thereafter, the personal computer 30 displaysthe message 54 a, the mode switching contents 54 b, and the OK key 54 c,as shown in FIG. 23(b).

In performing each of the above-described operations, data communicationbetween the personal computer 30, the control circuit 34 at the side ofthe R/W device, and the key-side control circuit 23 are effected asdescribed below. As shown in FIG. 4(a), when a command signal to “readdata (operational data, user data, and the like)” is outputted from thepersonal computer 30, the control circuit 34 at the side of the R/Wdevice receives the command signal from the personal computer 30 asshown in (d) and turns on or off the power amplifier 41. Simultaneously,as shown in (b), the control circuit 34 outputs to the key-side controlcircuit 23 a power signal which commands to “read data”, and thereafter,it is set in a receiving state.

When the key-side control circuit 23 receives the power signal from thecontrol circuit 34 at the side of the R/W device, as shown in (f), thecontrol circuit 23 is activated to determine the contents of a commandof the power signal (receiving state). Then, the key-side controlcircuit 23 is brought into a transmitting state by determining thecontents of a command, and reads out data 1, 2, . . . from thenonvolatile memory 26. Based on the data 1, 2, . . . , the controlcircuit 23 turns on or off the transistor 28 a of the modulation circuit28, and simultaneously, transmits the data 1, 2, . . . to the controlcircuit 34 at the side of the R/W device.

When the control circuit 34 at the side of the R/W device receives thedata 1, 2, . . . , as shown in (c), after frame synchronization, first,the control circuit 34 detects data 1, CRC1, and EOM based on detectionof SOM. Subsequently, as shown in (d), the control circuit 34 at theside of the R/W device detects a communication error of data 1 based onthe previously-received CRC1 and data 1 while detecting SOM, data 2,CRC2, and EOM. Then, when data 1 has no error, as shown in (e), thecontrol circuit 34 at the side of the R/W device transmits data 1 to thepersonal computer 30 while receiving data 2.

Meanwhile, CRC is a kind of error detection code and is short for theCyclic Redundancy Check. Further, EOM is a kind of code which indicatescompletion of data and is short for the End Of Message. Further, atransmission bit rate from the key-side control circuit 23 to thecontrol circuit 34 at the side of the R/W device is smaller than atransmission bit rate from the control circuit 34 at the side of the R/Wdevice to the personal computer 30.

The control circuit 34 at the side of the R/W device performs repeatedlyan operation for detecting an error of previous data while receivingdata and an operation for transmitting previous data to the personalcomputer 30 while receiving data. Here, as shown in (d), when thecontrol circuit 34 at the side of the R/W device detects an error ofdata m while receiving data m+1, first, the power amplifier 41 is turnedoff for a predetermined time, and at the same time, as shown in (b), astop pulse is outputted. Subsequently, a command to “read from data m”is transmitted.

When the key-side control circuit 23 receives the stop pulse, as shownin (f), the key-side control circuit 23 is switched from thetransmitting state to the receiving state. Then, the key-side controlcircuit 23 determines the contents of a command of a power signal to“read (retransmit) from data m” and transmits data m, data m+1, . . . tothe control circuit 34 at the side of the R/W device.

When the control circuit 34 at the side of the R/W device receives datam, data m+1, . . . , as shown in (c), after frame synchronization,first, the control circuit 34 detects data m, CRCm, and EOM based on thedetection of SOM. Subsequently, as shown in (d), the control circuit 34detects an error of data m while receiving SOM, data m+1, CRC m+1, andEOM. When data m has no error, as shown in (e), the control circuit 34transmits data m to the personal computer 30 while receiving data m+1.

When the control circuit 34 at the side of the R/W device finishesreceiving of SOM, data m+1, CRC m+1, and EOM, as shown in (d), thecontrol circuit 34 detects an error of data m+1 while receiving SOM,data m+2, CRC m+2, and EOM. When data m+1 has no error, as shown in (e),the control circuit 34 transmits data m+1 to the personal computer 30.At this time, when the control circuit 34 detects an end mark from datam+1, the control circuit 34 transmits data m+1 to the personal computer30 and completes the process. Further, output of a power signal to thekey-side control circuit 23 is stopped and the process ends.

Meanwhile, in FIG. 4, (a) shows contents of a command from the personalcomputer 30 to the R/W device 31, (b) shows contents of a command fromthe R/W device 31 to the transponder 20, and (c) shows contents of acommand from the transponder 20 to the R/W device 31. Further, (d) and(e) each show the operation of the R/W device 31 and (f) shows theoperation of the transponder 20.

Further, in performing each of the above-described operations, thecontrol circuit 34 at the side of the R/W device and the key-sidecontrol circuit 23 each correct the length of data in the same way as inFIG. 2. Namely, when the control circuit 34 at the side of the R/Wdevice receives a command signal from the personal computer 30, thecontrol circuit 34 transmits data to the key-side control circuit 23 atthe standard time.

On the other hand, the key-side control circuit 23 measures a datareceiving time (data length) based on the clock frequency of its own,and based on this measurement result, the key-side control circuit 23detects the variation of the clock frequency. Then, when the clockfrequency varies, the key-side control circuit 23 transmits to thecontrol circuit 34 at the side of the R/W device a “receiving-time(long) error signal” or “receiving-time (short) error signal”. As aresult, the control circuit 34 at the side of the R/W device correctsthe length of data and retransmits to the key-side control circuit 23.

According to the above-described embodiment, when the storage capacityof the transponder 20 (i.e., the storage capacity of the operationaldata area) becomes full, the vehicle-side controller 12 writesoperational data in the nonvolatile memory 13 a of its own, and when thetransponder 20 is initialized, the operational data stored in thevehicle-side controller 12 is written in the transponder 20. For thisreason, even when the storage capacity of the transponder 20 becomesfull, the operational data is stored. Accordingly, in the situation inwhich it is difficult that the key 19A is initialized in such a manneras to be carried into the office 29 as well, the operational data canreliably be recorded.

Further, the state in which the operational data is written in thevehicle-side controller 12 is notified. For this reason, the state inwhich the storage capacity of the transponder 20 is in a full state isindirectly notified, and therefore, a driver is required to performinitialization of the key 19A.

Moreover, the state in which the operational data stored in thevehicle-side controller 12 be written in the transponder 20 is notified.For this reason, there are prevented such circumstances that the key 19Ais pulled out during writing of the operational data so that thecommunication between the vehicle-side controller 12 and the transponder20 is interrupted, and at the same time, the writing of operational datais inadvertently impeded.

Further, the transponder 20 has the function of determining variation ofa clock frequency and the vehicle-side controller 12 and the R/W device31 each have the function of correcting data length. For this reason, itbecomes unnecessary that the transponder 20 exclusively has a complextime correction function in which the variation of a clock frequency isdetermined and the data length is corrected. Accordingly, theperformance of communication between the vehicle-side controller 12 andthe transponder 20 and between the R/W device 31 and the transponder 20improves without imposing any functional load on the transponder 20 tothe utmost.

In this case, so long as setting is such that SOM (=8To), data 1 (=4To),and data 0 (=To), it is easy to discriminate SOM, data 1, and data 0,and therefore, the communication can be carried out relativelyaccurately without being influenced by the variation of the clockfrequency. However, the time for communication becomes long. On theother hand, in the above-described embodiment, since setting is suchthat SOM (=4To), data 1 (=2To), and data 0 (=To), there is an advantagein that the time for communication is shortened.

FIG. 3 shows the relationship between the clock frequency of thetransponder 20 and the communication enable range. As shown in thisfigure, communication is allowed only in the (standard) range ofallowance (of ±30%) in a conventional system. However, in the presentembodiment, communication is allowed even in the ranges which exceed theallowance.

The data length from the vehicle-side controller 12 and the data lengthfrom the R/W device 31 are measured, and when the measurement result isnot obtained in the standard range, it is determined that the clockfrequency varies. For this reason, different from the case in which theoperating voltage of the transponder 20 is detected to determine thevariation of the clock frequency, it becomes unnecessary to use avoltage sensor, and therefore, the transponder 20 is prevented frombeing made larger. At the same time, the variation of the clockfrequency is measured based on the data length from the vehicle-sidecontroller 12 and the data length from the R/W device 31, and therefore,the variation of the clock frequency can be accurately detected.

When an error of communication from the transponder 20 to the R/W device31 is determined by the R/W device 31 and no communication error isdetected, data from the transponder 20 is transmitted to the personalcomputer 30. When a communication error is detected, a command toretransmit data is given to the transponder 20. For this reason, thereis no possibility that useless data (data having a communication error)is transmitted from the R/W device 31 to the personal computer 30,thereby resulting in the time for communication being shortened.

When it is determined by the R/W device 31 that the data from thetransponder 20 is the final operational data and user data and the finaloperational data and user data are detected, transmission of subsequentdata to the personal computer 30 is stopped. For this reason, there isno possibility that useless data (initialization data and the like) istransmitted from the R/W device 31 to the personal computer 30, andtherefore, in this point as well, the time for communication can beshortened.

When no communication error is found in the data from the transponder20, the R/W device 31 concurrently performs the operation for receivingdata from the transponder 20 and the operation for transmitting to thepersonal computer 30 the data previously received from the transponder20. For this reason, as compared with a case in which after detection ofan error in the data received from the transponder 20, data istransmitted to the personal computer 30 in a collective manner, the timefor communication is shortened still further.

When a communication error is found in the data from the transponder 20,a command to “retransmit, first, data having an error” is given from theR/W device 31 to the transponder 20. For this reason, transmissionstarts again serially from the data having a communication error.Accordingly, as compared with the case in which transmission startsagain from initial data, the time for communication is shortened stillfurther.

Further, the communication of operational data is performed between thevehicle-side controller 12 and the R/W device 31 with the key 19Aserving as a medium. For this reason, it is different from aconventional system in which communication of operational data isperformed with an IC card serving as a medium, carrying both the key 19Aand the IC card becomes unnecessary, and as a result, convenience foruse improves. Particularly, in a case of a special vehicle such as theconstruction vehicle 11, the inconvenience of carrying both the key 19Aand the IC card in a work site can be eliminated, and therefore, thepresent system is even more advantageous in terms of convenience foruse.

Moreover, communication of operational data is performed by using anexisting hard structure which allows security (immobilizer and doorsecurity). For this reason, writing of operational data resulting fromthat an engine is started by an unregistered key is prevented, which isadvantageous in terms of data security.

The user data is written in the key-side nonvolatile memory 26 via thepersonal computer 30 and the R/W device 31 or the user data is read outfrom the nonvolatile memory 26. For this reason, it becomes unnecessaryto carry an IC card or a notebook having user data written therein, andtherefore, convenience for use is further improved.

Next, a second embodiment of the present invention will be describedbased on FIG. 26. In addition to the control (see FIG. 1) in which afterdetection of the state in which the storage capacity at the key side isin a full state, operational data is written in an operational data areaowned by the vehicle-side control circuit 13, the vehicle-side controlcircuit 13 indicates a remaining storage capacity at the key side, aswill be described later, and requires initialization for the key-sideoperational data area.

When an engine is started, the process proceeds to step S41 in FIG. 26and the vehicle-side control circuit 13 reads the storage capacity ofthe nonvolatile memory 26 (the storage capacity of the operational dataarea) and the value of the R/W update counter from the key-side controlcircuit 23. The process proceeds to step S42 in which it is determinedwhether the value of the R/W update counter and a previously-read valuecoincide with each other. For example, when the present value of the R/Wupdate counter and the previously-read value coincide with each other,it is determined that the operational data area has not beeninitialized, and the process proceeds from step S42 to step S43.

When the process proceeds to step S43, the vehicle-side A controlcircuit 13 writes the operational data in the key-side nonvolatilememory 26 with the key-side writing start address A set at the head, andthereafter, the process proceeds to step S44. Then, the vehicle-sidecontrol circuit 13 updates the key-side writing start address A andwrites in the memory (RAM) of its own, and thereafter, the processproceeds to step S45.

When the process proceeds to step S45, the vehicle-side control circuit13 calculates, based on the storage capacity at the side of a key havingbeen detected in step S41 and the writing start address A at the keyside, a remaining capacity of the memory in which operation data can bewritten. Then, the process proceeds to step S46 in which thevehicle-side control circuit 13 controls to drive the LEDs 18 a 1 to 18e 1, and at the same time, displays the remaining storage capacity atthe key side.

In this case, the nonvolatile memory 13 a of the vehicle-side controlcircuit 13 stores reference time Tma, Tmb (<Tma). When the vehicle-sidecontrol circuit 13 calculates the remaining storage capacity, first, itconverts the remaining storage capacity to remaining time Tm in whichdata can be written. Subsequently, the remaining time Tm is comparedwith the reference time Tma, and in the case of “Tm<Tma”, the LEDs 18 a1 to 18 e 1 are turned on and off at a predetermined low interval.Thereafter, in the case of “Tm <Tmb”, the LEDs 18 a 1 to 18 e 1 areturned on and off at a predetermined high interval, and at “Tm=0”, theLEDs 18 a 1 to 18 e 1 are held in a lighted state.

Further, when the vehicle-side control circuit 13 detects that thepresent value and the previous value of the R/W update counter do notcoincide with each other” in step S42, it is determined that theoperational data area has been initialized and the process proceeds fromstep S42 to step S47. Then, the vehicle-side control circuit 13 writesthe operational data in the key-side nonvolatile memory 26 with aninitial address set at the head, and thereafter, the process proceeds tostep S44.

According to the above-described embodiment, the vehicle-side controller12 detects the remaining storage capacity of the transponder 20 (theremaining storage capacity of the operational data area) and notifiesthe detected result. For this reason, the driver can easily performmanagement in which the key 19A is initialized in a state of beingcarried into the office 29, and therefore, the operational data can bereliably recorded.

When the remaining storage capacity of the transponder 20 is less thanthe predetermined value, the detected result of the remaining storagecapacity is notified. For this reason, there is prevented such asituation that the driver receives useless information in that theremaining storage capacity is large, so as to induce inadvertentattention.

Further, the lighted state of the LEDs 18 a 1 to 18 e 1 is changed inaccordance with the remaining storage capacity of the transponder 20,and therefore, the remaining storage capacity is notified relativelyroughly.

Meanwhile, in the above-described second embodiment, the vehicle-sidecontrol circuit 13 has both the function of storing the operational dataand the function of notifying the remaining storage capacity of theoperational data, but the present invention is not limited to the same.For example, the function of storing the operational data may becancelled.

In the above-described first and second embodiments, in order that theremaining storage capacity of the operational data area be notified, thelighted state of the LEDs 18 a 1 to 18 e 1 is changed. However, thepresent invention is not limited to the same. For example, the lightedstate of any one, any two, any three, or any four of the LEDs 18 a 1 to18 e 1 may be changed. Alternatively, with a 7-segment or bar-graphdisplay device being connected to the vehicle-side control circuit 13,the remaining storage capacity may be displayed on the display device ina numeric or graphic manner.

In the above-described first and second embodiments, there is provided astructure in which when the remaining storage capacity Tm of theoperational data area is less than the reference values Tma, Tmb, theremaining storage capacity Tm is notified. However, the presentinvention is not limited to the same and the remaining storage capacitymay be constantly notified. In this case, the remaining storage capacitymay be notified by the change of the lighted state of the LEDs 18 a 1 to18 e 1 or may be indicated by a 7-segment display or a bar-graphdisplay. Particularly, when the remaining storage capacity is indicatedby the 7-segment display or the bar graph display, there is an advantagein that the remaining storage capacity be notified closely andaccurately.

In the above-described first and second embodiments, the state in whichthe vehicle-side controller 12 writes operational data in thenonvolatile memory 13 a and the state in which the vehicle-sidecontroller 12 writes the operational data of the nonvolatile memory 13 ain the transponder 20 are notified by the lighted state of the LED 18 a1, but the present invention is not limited to the same. For example,these states may also be notified by turning on or turning on and offany one, any two, any three, or any four of the LEDs 18 a 1 to 18 e 1.

Further, in the above-described first and second embodiments, the statein which the vehicle-side controller 12 writes operational data in thenonvolatile memory 13 a and the state in which the vehicle-sidecontroller 12 writes the operational data of the nonvolatile memory 13 ain the transponder 20 are notified using light, but the presentinvention is not limited to the same. For example, these states may alsobe notified by using a display or using a voice through a speaker.Particularly, in the case of using a display, a 7-segment display, abar-graph display, or the like may be used.

In the above-described first and second embodiments, the R/W device 31is driven by an external power source (commercial alternating currentpower source), but the present invention is not limited to the same. Forexample, the R/W device 31 may also be driven by an internal powersource such as a battery, built in the R/W device 31.

Further, in the above-described first and second embodiments, thedesktop personal computer 30 is illustrated as an external controller,but the present invention is not limited to the same. For example, aportable notebook-sized personal computer, subnotebook-sized personalcomputer, or the like may also be used.

In the above-described embodiments, the digit switch 18 g is used forsetting the internal clock of the vehicle-side controller 12, but thepresent invention is not limited to the same. When a clock and a setswitch are used, for example, as in general vehicles, a minute of theclock may be set at “0” by operation of the set switch. In this case,with a display portion of the clock being comprised of a 7-segmentdisplay device, it suffices that the state in which the vehicle-sidecontroller 12 writes operational data in the nonvolatile memory 13 a,the state in which the vehicle-side controller 12 writes the operationaldata of the nonvolatile memory 13 a in the transponder 20, and theremaining storage capacity of the nonvolatile memory 26 may each bedisplayed in the display device.

In the above-described first and second embodiments, the user data iswritten in the transponder 20 via the personal computer 30 and the R/Wdevice 31, but the present invention is not limited to the same. Forexample, a user data writing function may be canceled. In the structureprovided above, the R/W device 31 functions as a device exclusively usedas a reader for reading operational data from the transponder 20.

In the above-described first and second embodiments, the key detectionswitch 39 provided in the R/W device 31 is used to detect whether thekey 19A or 19B has been inserted in the key insertion opening 38 a.However, the present invention is not limited to the same. For example,the key detection switch 39 does not need to be provided. In this case,the R/W device 31 cannot communicate with the transponder 20 even if ittries to communicate therewith. Accordingly, at this point in time, theabsence of the key is detected and can be displayed on the image surfaceof the personal computer 30.

Further, in the above-described first and second embodiments, thetransponder 20 is built-in in the key 19A and 19B, but the presentinvention is not limited to the same. For example, the transponder 20may be built-in in a card (an IC card may be used as atransmitting/receiving device).

Moreover, in the above-described first and second embodiments, an errorof “N−1”-th data is detected while receiving N-th data from thetransponder 20, but the present invention is not limited to the same.For example, an error of “N−2”-th data or an error of “N−3”-th data maybe detected. In short, it suffices that an error of apreviously-received data be detected.

In the above-described first and second embodiments, “N−1”-th data istransmitted to the personal computer 30 while receiving N-th data fromthe transponder 20, but the present invention is not limited to thesame. For example, “N−2”-th data may be transmitted while receiving N-thdata. In short, it suffices that previously-received data betransmitted.

In the above-described first and second embodiments, the operation ofreceiving data from the transponder 20 and the operation of transmittingthe data previously received from the transponder 20 to the personalcomputer 30 are carried out concurrently, but the present invention isnot limited to the same. For example, after errors have been detected inall data received from the transponder 20, such data may be collectivelytransmitted to the personal computer 30.

In the above-described first and second embodiments, there is providedthe structure in which a start-up time of an engine and a past historyof security are transmitted from the vehicle-side controller 12, but thepresent invention is not limited to the same. For example, a travelingspeed of the vehicle 11, the number of times of braking, an abnormalstate of each of various sensor, and the like are detected and may betransmitted as operational data.

In the above-described first and second embodiments, an operational dataarea is provided in the nonvolatile memory 13 a at the side of a vehicleand operational data is written in the operational data area, but thepresent invention is not limited to the same. For example, a nonvolatilememory exclusively used for writing operational data may be provided.

Further, in the above-described first and second embodiments, thepresent invention is applied to the construction vehicle 11, but thepresent invention is not limited to the same. For example, the presentinvention may also be applied to an automobile. In this case, inputtingof a secret identification code is effected in such a manner that theregular key 19A or the master key 19B is inserted in the ignition keycylinder and an operation set including the following operations (1) and(2) is carried out four times (sets). Further, in order to detect an IDcode from the key 19A and 19B, the ID code is detected based on thestarter switch 11 a being turned to ACC and it suffices that adetermination about that the ID code has been registered be made. (1)The key 19A or the key 19B is turned N times in the order of,(ACC)→ON→ACC. (2) The key 19A or the key 19B is turned only once in theorder of, (ACC)→OFF→ACC.

As clearly seen from the foregoing, the data carrier system of thepresent invention has the following effects.

According to means described in claim 1, when the storage capacity of areceiving device becomes full, a vehicle-side control device writesoperational data in a storage portion of its own, and when the receivingdevice is initialized, the operational data stored in the vehicle-sidecontrol device is written in the receiving device. For this reason, evenwhen the storage capacity of the receiving device becomes full, theoperational data is stored. Accordingly, even when the receiving deviceis initialized in the state of being carried into an office or the like,the operational data can reliably be recorded.

According to means described in claim 2, the state in which operationaldata is written in a vehicle-side control device is notified. For thisreason, the state in which the storage capacity of the receiving deviceis in a full state is indirectly notified, and therefore, a driver isrequired to perform initialization for the receiving device.

According to means described in claim 3, the state in which operationaldata stored in a vehicle-side control device is written in a receivingdevice is notified. For this reason, there is prevented such a situationthat the communication between the vehicle-side control device and thereceiving device is interrupted during writing of the operational dataand the writing of operational data is thereby impeded inadvertently.

According to means described in claim 4, a vehicle-side control devicedetects and indicates a remaining storage capacity of a receivingdevice. For this reason, it is possible for a driver to easily performmanagement in which the receiving device is initialized in a state ofbeing carried into an office or the like, and therefore, operationaldata can reliably be recorded.

According to means described in claim 5, when the remaining storagecapacity of the receiving device is lower than a predetermined value, aresult of detection of the remaining storage capacity is notified. Forthis reason, there is prevented such a situation that the driverreceives useless information in that the remaining storage capacity islarge, so as to induce inadvertent attention.

According to means described in claim 6, a lighted state of a lightsource is changed in accordance with the remaining storage capacity of areceiving device, and therefore, the remaining storage capacity isnotified relatively roughly.

According to means described in claim 7, the remaining storage capacityof a receiving device is displayed in a numeric or graphic manner, andtherefore, the remaining storage capacity is notified relativelyexactly.

What is claimed is:
 1. A data carrier system characterized bycomprising: a vehicle-side control device installed in a vehicle andtransmitting operational data of the vehicle; and a receiving device forreceiving operational data transmitted from the vehicle-side controldevice, wherein the receiving device includes a receiving-device-sidestorage portion which stores received operational data, and saidvehicle-side control device includes: a storage capacity detectingportion for detecting the amount of operational data stored in saidreceiving-device-side storage portion and an initialization detectingportion for detecting that said receiving-device-side storage portion isinitialized such that the amount of operational data stored in saidreceiving-device-side storage portion is zero, and avehicle-side-control-device-side storage portion which stores theoperational data, and when said storage capacity detecting portiondetects that the amount of operational data stored in saidreceiving-device-side storage portion is in a full state, thevehicle-side control device writes operational data in saidvehicle-side-control-device-side storage portion, and when said storagecapacity detecting portion detects that said receiving-device-sidestorage portion is initialized, the vehicle-side control device writesthe operational data stored in said vehicle-side-control-device-sidestorage portion in said receiving-device-side storage portion of thereceiving device.
 2. A data carrier system according to claim 1,characterized in that the vehicle-side control device further includes anotifying portion which indicates that operational data is written insaid vehicle-side-control-device-side storage portion of thevehicle-side control device.
 3. A data carrier system according to claim1, characterized in that the vehicle-side control device furtherincludes a notifying portion which indicates that operational datastored in said vehicle-side-control-device-side storage portion is beingwritten in said receiving-device-side storage portion of the receivingdevice.
 4. A data carrier system characterized by comprising: avehicle-side control device installed in a vehicle and transmittingoperational data of the vehicle; and a receiving device for receivingoperational data transmitted from the vehicle-side control device,wherein the receiving device includes a storage portion which storesreceived operational data, and said vehicle-side control deviceincludes: a remaining storage capacity detecting portion which detectsthe remaining storage capacity of said storage portion; and a notifyingportion which indicates a result of detection of the remaining storagecapacity.
 5. A data carrier system according to claim 4, characterizedin that when the result of detection of the remaining storage capacityis lower than a predetermined value, the vehicle-side control deviceindicates the result of detection.
 6. A data carrier system according toclaim 4, characterized in that the notifying portion is comprised of alight source whose lighted state changes in accordance with theremaining storage capacity.
 7. A data carrier system according to claim4, characterized in that the notifying portion is comprised of a displayportion which displays the remaining storage capacity in a numeric orgraphic display.
 8. A data carrier system according to claim 1,characterized in that the receiving device is incorporated in a vehiclekey of the vehicle.
 9. A data carrier system according to claim 1,characterized by further comprising a reading device which is providedseparately from the vehicle and which can initialize saidreceiving-device-side storage portion and/or can read-out, accumulateand store the operational data stored in said receiving-device-sidestorage portion.
 10. A data carrier system according to claim 8,characterized by further comprising a reading device which is providedseparately from the vehicle and which can initialize saidreceiving-device-side storage portion and/or can read-out, accumulateand store the operational data stored in said receiving-device-sidestorage portion.
 11. A data carrier system according to claim 1,characterized in that said vehicle-side control device furthercomprises: a remaining storage capacity detecting portion which detectsremaining storage capacity of said receiving-device-side storageportion; and a notifying portion which notifies a result of detection ofthe remaining storage capacity.
 12. A data carrier system according toclaim 11, characterized in that when the result of detection of theremaining storage capacity is lower than a predetermined value, thevehicle-side control device indicates the result of detection.
 13. Adata carrier system according to claim 11, characterized in that thenotifying portion is comprised of a light source whose lighted statechanges in accordance with the remaining storage capacity.
 14. A datacarrier system according to claim 11, characterized in that thenotifying portion is comprised of a display portion which displays theremaining storage capacity in a numeric or graphic display.